Throw away insert boring bars are conventionally machined from round bar stock which is sufficiently oversize relative to the finished boring bar diameter to provide stock for an offset support under the cutting corner of a throw away insert installed thereon. The machining operation is normally performed by turning down to suitable diameter the entire length of the boring bar with the exception of the cutting end which is thereupon further machined to provide for chip clearance and an insert pocket. This machining also involves removal of superfluous end stock which does not directly contribute to the offset support of the cutting insert. Such conventional manufacturing procedures involve a considerable amount of machining with a number of machining setups required in addition to those involved in providing the chip relief and insert pocket. A large amount of scrap material is involved in such procedures.
Relatively small diameter boring (less than 1/2 inch diameter) are known to have been produced singly by providing asharp 90.degree. offset bend at the cutting end which was heat treated and ground with an integral cutting point. The severe forming of a sharp right angle bend required heating of the end to a forging temperature and heat treatment of the bar following the bending operation to harden the material. Such heat treatment results in distortion of the bar shape along its length; and the entire bar must be constructed of relatively expensive tool steel in order to provide a durable cutting point.